In many manufacturing operations, particularly with respect to plastic fabrication, it is not uncommon for some of the raw plastic resin materials, typically in pellet form, which are molded or extruded in the operation to be shipped to the manufacturing facility in heavy containers, e.g drums, barrels, Gaylords, Octobins, bulk trucks, rail cars, silo, day bins, flat bottom bins, or other utility bins that may or may not have a sloped bottom or flat bottom. Drums are typically fiber drums that are typically cylindrical, but can be other shapes as well, and usually hold between 200 to 250 lbs of material. Barrels can be the traditional barrels such as those made with staves of wood or other suitable material including metal and plastic. “Gaylords” are cubical corrugated containers, usually with a 1000 pound weight limit and are often made of cardboard material; however, they are not limited to this material and may be plastic. Octobins are similar.
Any of these containers may be delivered by any number of means to the manufacturing facility and are stored until they are required for use in the manufacturing process. The containers can be stored anywhere on the manufacturing site as desired and can be transported from the storage location by any suitable means such as by a fork lift, a conveyor belt, etc. Once the plastic resin pellets in the container are needed, the forklift or other device removes the container from the storage site and transports it to the location where the contents are needed. There, the container is either emptied all at once by dumping or only portions of the contents are manually removed from time to time, on an as needed basis. Typically these filled containers are too heavy to be lifted by a person and mechanical means are necessary to dump the contents, or workers use shovels and scoops to manually remove the material.
For particulate materials stored in such containers, such as plastic resin pellets, powders, and the like, vacuum or similar conveyance means can be used to remove the material from the container and transport the material through piping or tubing, or other similar means used in conveying material, to wherever the material is needed for manufacturing purposes. It is typical to use vacuum to empty these containers with a wand directly or indirectly coupled to a vacuum source. The wand is placed in the container and is either manually forced to the bottom by an operator or placed on the top of the contents of the container and allowed to suction its way to the bottom. The wand is stationary. Thus, it can only suction the contents of the container that are immediately around the wand. To this end, without operator assistance to re-position the wand, vacuum is inefficient to remove all of the particulate material and may leave as much as half the contents within the container. Accordingly, an operator must constantly monitor the wand and manually adjust it to ensure all of the material is removed from the container. This is costly in terms of labor and lost production.
One approach to this problem is addressed in European patent EP 1 199 266, disclosing a device and method for evacuating bulk material. Specifically, EP 1 199 266 teaches a suction apparatus that may be lowered into a sack-like container. The suction apparatus, once inserted into the sack, rests on top of the bulk resin contained therein and sinks as the resin is evacuated. The container is coupled to a lift which is adapted to raise and lower the sack. As the sack is raised, the diameter of the sack reduces, thereby forcing the resin toward the center of the container and allowing the suction to reach substantially all of the resin. In this approach, the container must be one that is easily manipulated. In other words, the approach is limited to a sack and does not provide a solution for evacuating resin from more rigid containers, e.g. drums, barrels, Gaylords, bulk trucks, rail cars, silos, day bins, flat bottom bins, or other utility bins.
Thus, there remains a need in the art for apparatus and methods for removing particulate material, particularly granular plastic resin pellets, powder, and the like, from a relatively rigid storage container and especially from rectangular, or cubical, or containers having concave angular interior corners, particularly right angle interior corners, without operator intervention or manipulation of the container.